Poiseuille ’ s Formula
The rate of flow ( v ) of liquid through a horizontal pipe for steady flow is given by
where , p = pressure difference across the two ends of the tube . r = radius of the tube , n = coefficient of viscosity and 1 = length of th tube .
The Rate of Flow of Liquid Rate of flow of liquid through a tube is given by v = ( P / R ) where , R = ( 8 ηl / πr 4 ), called liquid resistance and p = liquid pressure . ( i ) When two tubes are connected in series Resultant pressure difference p = p1 + p2
Rate of flow of liquid ( v ) is same through both tubes . Equivalent liquid resistance , R = R1 + R2
( ii ) When two tubes are connected in parallel 1 . Pressure difference ( p ) is same across both tubes . 2 . Rate of flow of liquid v = v1 + v2 3 . Equivalent liquid resistance ( 1 / R ) = ( 1 / R1 ) + ( 1 / R2 ) Stoke ’ s Law
When a small spherical body falls in a long liquid column , then after sometime it falls with a constant velocity , called terminal velocity . When a small spherical body falls in a liquid column with terminal velocity then viscous force acting on it is
F = 6πηrv